Leak Preventing Device and Tank for Transporting Liquid With such a Device

ABSTRACT

A leak preventing device ( 1 ) for preventing liquid from leaking out of a damaged tank ( 2 ), the device comprising:—a floating body ( 4 ) capable of floating at the surface ( 3 ) of the liquid in the tank; and—a flexible hose ( 5 ), the first end of the hose being fixed to the floating body and the hose being fixed to a wall of the tank at a point of attachment ( 8 ) at a distance from said first end, wherein the hose extends freely inside the tank between the floating body and said point of attachment and wherein the second end of the hose is connectable to a suction side of a vacuum pump( 9 ) so as to allow gas to be drawn off via the hose from a gas-filled space ( 10 ) in the tank above the surface of the liquid in order to produce an under pressure in said space. The invention also relates to a tank for transporting liquid provided with such a device.

FIELD OF THE INVENTION AND PRIOR ART

The present invention relates to a leak preventing device according tothe preamble of claim 1 for preventing liquid from leaking out of adamaged tank. The invention also relates to a tank for transportingliquid provided with such a device.

Liquid fuel and other types of liquids may be transported and stored intanks of various types. If such a tank is damaged, for instance due toan accident or wear, the liquid in the tank may leak to the surroundingenvironment, which may cause a lot of problem, for instance in the formof material damages, environmental pollution and health and safetyhazards for people in the vicinity of the leaking tank. It is previouslyknown, for instance from GB 1 020 581 A and DE 1 525 465 B, that liquidmay be prevented from leaking out through a leak below the surface ofthe liquid in a tank by producing a sufficient underpressure in agas-filled space above the surface of the liquid in the tank by means ofa vacuum pump.

A leak preventing device is previously known from WO 87/02650 A1. Thispreviously known device has the form of a leak sealing pad which is tobe attached to an outer wall of a tank so as to cover a leak opening inthe tank wall and thereby prevent gas or liquid from flowing out of thetank through the leak opening. The pad is pressed against the tank wallunder the effect of an underpressure generated in a vacuum chamber ofthe pad by means of a vacuum pump. However, this leak preventing deviceis only suitable for use when it comes to an easily accessible leakconcentrated to a limited area.

OBJECT OF THE INVENTION

The object of the present invention is to provide a new and favourableleak preventing device for preventing liquid from leaking out of adamaged tank.

SUMMARY OF THE INVENTION

According to the present invention, the above-mentioned object isachieved by a leak preventing device having the features defined inclaim 1.

The leak preventing device of the present invention comprises:

-   -   a floating body with a buoyancy which makes it capable of        floating at the surface of the liquid in the tank with at least        an upper part of the floating body located above the surface of        the liquid in the tank; and    -   a flexible hose with a first end and an opposite second end, the        first end of the hose being fixed to the floating body and the        hose being fixed to a wall of the tank at a point of attachment        at a distance from said first end, wherein the hose extends        freely inside the tank between the floating body and said point        of attachment and wherein the second end of the hose is        connected or connectable to a suction side of a vacuum pump so        as to allow gas to be drawn off via the hose from a gas-filled        space in the tank above the surface of the liquid in the tank in        order to produce an underpressure in said space.

With the leak preventing device of the present invention, aleak-preventing underpressure may be achieved inside a tank in a simplemanner. When liquid leaks out of the tank through a leak below thesurface of the liquid in the tank, for instance when the tank has beendamaged due to an accident, a vacuum pump is to be connected to theflexible hose inside the tank and the vacuum pump is to be operated inorder to draw off gas from the gas-filled space in the tank above thesurface of the liquid in the tank via the flexible hose and therebyproduce an underpressure in said space sufficient for preventing liquidfrom continuing to leak out of the tank through said leak. The floatingbody will always float at the surface of the liquid in the tankirrespective of the prevailing inclination of the tank, and the floatingbody may thereby ensure that the flexible hose always is maintained influid communication with the gas-filled space in the tank above thesurface of the liquid in the tank. Furthermore, the leak preventingdevice of the present invention may be used even if the leak opening isinaccessible.

According to an embodiment of the invention, said first end of the hoseis fixed to the floating body in such a manner that the hose projectsfrom the underside of the floating body at the centre thereof. Hereby,the weight of the hose will contribute in keeping the floating bodyfloating in a correct position with its underside facing verticallydownwards.

According to another embodiment of the invention, said second end of thehose is connected to a shut-off valve, which is fixed to the tank andaccessible from the outside of the tank. The shut-off valve makes iteasy to put the flexible hose inside the tank in communication with avacuum pump when so needed and to otherwise keep the flexible hosedisconnected from the ambient air.

According to another embodiment of the invention, said shut-off valve isconnected to a coupling member, which is configured for releasableengagement with a corresponding coupling member arranged at an end of asuction hose from a vacuum pump. Hereby, a vacuum pump may easily andrapidly be connected to the flexible hose inside the tank when soneeded.

According to another embodiment of the invention, the flexible hose isconnected to one or more further shut-off valves, which are fixed to thetank at a distance from each other and accessible from the outside ofthe tank, wherein each such further shut-off valve is connected to acoupling member which is configured for releasable engagement with acorresponding coupling member arranged at an end of a suction hose froma vacuum pump. Each shut-off valve with its associated coupling memberconstitutes an access point through which a vacuum pump may be connectedto the flexible hose inside the tank. By providing several such accesspoints, the risk that the tank, in connection with an accident, wouldend up in a position in which no access to the flexible hose inside thetank is possible is reduced.

Further advantageous features of the leak preventing device of thepresent invention will appear from the following description and thedependent claims.

The invention also relates to a tank for transporting liquid having thefeatures defined in claim 11.

Further advantageous features of the tank of the present invention willappear from the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

With reference to the appended drawings, a specific description ofembodiments of the invention cited as examples follows below. In thedrawings:

FIG. 1 is a schematic longitudinal section through a tank provided witha leak preventing device according to an embodiment of the presentinvention,

FIG. 2 is a schematic longitudinal section through the tank of FIG. 1,as seen with a vacuum pump connected to the flexible hose inside thetank,

FIG. 3 is a detail enlargement of the encircled area III in FIG. 1

FIG. 4 is a detail enlargement of the encircled area IV in FIG. 2,

FIG. 5 is a schematic perspective view from below of a floating bodyincluded in the leak preventing device of FIG. 1,

FIG. 6 is a schematic perspective view from above of the floating bodyof FIG. 5,

FIG. 7 is a schematic vertical section through the floating body ofFIGS. 5 and 6,

FIG. 8 is a schematic planar view from above of the floating body ofFIGS. 5 and 6, and

FIG. 9 is a schematic vertical section through a floating body accordingto an alternative variant.

DETAILED DESCRIPTION OF EMBODIMENTS OF THE INVENTION

A leak preventing device 1 according to an embodiment of the presentinvention is schematically illustrated in FIGS. 1-4. The leak preventingdevice 1 is to be used with a tank 2 for transporting and/or storingliquid in order to prevent liquid from leaking out of the tank through ahole or crack in a wall of the tank below the surface 3 of the liquid inthe tank if the tank is damaged due to an accident or wear. Thus, theleak preventing device 1 is to be pre-mounted to the tank 2 so as to beready for use in a possible situation when the tank is damaged andliquid starts to leak out of the tank.

The leak preventing device 1 comprises a floating body 4 which isconfigured to have such a buoyancy that it is capable of floating at thesurface 3 of the liquid in the tank 2 with at least an upper part of thefloating body 4 located above the surface 3 of the liquid in the tank.The leak preventing device 1 also comprises a flexible hose 5 with afirst end 6 a and an opposite second end 6 b. The first end 6 a of thehose is fixed to the floating body 4 and the hose 5 is fixed to a wall 7of the tank 2 at a point of attachment 8 at a distance from said firstend 6 a, wherein the hose 5 extends freely inside the tank 2 between thefloating body 4 and said point of attachment 8. The second end 6 b ofthe hose is connected or connectable to a suction side of a vacuum pump9 (see FIG. 2) so as to allow the vacuum pump to draw off gas via thehose 5 from a gas-filled space 10 in the tank 2 above the floating body4 and above the surface 3 of the liquid in the tank in order to reducethe pressure in said space 10 to such a low value that leakage of liquidfrom the tank 2 through a possible leak below the surface 3 of theliquid is prevented.

In the illustrated embodiment, the second end 6 b of the hose isconnected to a shut-off valve 11, which is fixed to the tank 2 andaccessible from the outside of the tank. The shut-off valve 11 isconnected to a coupling member 13 which is configured for releasableengagement with a corresponding coupling member 14 (see FIG. 4) arrangedat an end of a suction hose 15 from a vacuum pump 9.

The flexible hose 5 is with advantage connected to two or more shut-offvalves 11 which are fixed to the tank 2 at a distance from each otherand accessible from the outside of the tank 2, as illustrated in FIGS.1-4, wherein each shut-off valve 11 is connected to a coupling member 13configured for releasable engagement with a corresponding couplingmember 14 arranged at an end of a suction hose 15 from a vacuum pump 9.In the illustrated example, the leak preventing device 1 comprises threeshut-off valves 11 with associated coupling members 13. The shut-offvalves 11 are connected to each other by means of connecting pipes 16which are mounted to the tank 2 on the outside thereof. The connectingpipes 16 may as an alternative be mounted inside the tank 2.

Each shut-off valve 11 comprises a valve member (not shown) which ismoveable by means of a maneuvering member 12 between a closed positionand an open position. The maneuvering member 12 may for instance havethe form of a lever or knob.

In the illustrated embodiment, the suction hose 15 of the vacuum pump 9is to be connected to one of the shut-off valves 11 when need arises.However, the leak preventing device of the present invention may as analternative comprise a vacuum pump which is permanently connected to theflexible hose 5 inside the tank 2 via a shut-off valve 11.

The first end 6 a of the flexible hose 5 is with advantage fixed to thefloating body 4 in such a manner that the hose 5 projects from theunderside 17 a of the floating body at the centre thereof, asillustrated in FIGS. 5 and 7. In the embodiments illustrated in FIGS.5-9, the floating body 4 is provided with a suction channel 18, whereinthe first end 6 a of the flexible hose 5 is connected to a lower end 19a of the suction channel 18 and an inlet opening 20 is arranged at anupper end 19 b of the suction channel 18. The inlet opening 20 isprovided in a part of the floating body 4 which is configured to belocated above the surface 3 of the liquid in the tank 4 when thefloating body 4 is floating at the surface 3 of the liquid in the tank.In the illustrated examples, the suction channel 18 extends across thefloating body 4 from the underside 17 a of the floating body to theupper side 17 b thereof along the centre axis of the floating body 4.

In the embodiment illustrated in FIGS. 5-8, the inlet opening 20 of thesuction channel 18 is arranged at the upper end of a pipe 21 whichprojects from the upper side 17 b of the floating body 4, wherein theupper end of the pipe 21 is received in a cover 22 which is configuredto prevent liquid from splashing into the suction channel 18 through theinlet opening 20. The cover 22 is fixed to the pipe 21 by means of asupporting member 23 in the form of a plate or the similar, wherein gasis allowed to flow into the cover 22 towards the inlet opening 20 of thesuction channel 18 through gaps 24 between the supporting member 23 andan inner wall of the cover 22, as illustrated in FIGS. 7 and 8, orthrough gaps in the supporting member 23.

In the embodiment illustrated in FIG. 9, a check valve 25 is arranged atthe inlet opening 20 of the suction channel 18 in order to keep theinlet opening closed when no gas to is drawn off via the flexible hose 5from the gas-filled space 10 above the surface 3 of the liquid in thetank 2. The check valve 25 comprises a valve member 26, for instance inthe form of a disc, which is moveably mounted to the float 4 at theupper end 19 b of the suction channel 18. Under the effect of a suctioneffect in the suction channel 18 produced by a vacuum pump 9, the valvemember 26 is moveable from a closed position, in which the valve member26 covers the inlet opening 20 of the suction channel 18 and therebyprevents liquid from splashing into the suction channel 18 through theinlet opening 20, to an open position, in which the valve member 26 isswung away from the inlet opening 20. A stop member 27 is with advantagearranged at the inlet opening 20 of the suction channel 18 in order todefine the closed position of the valve member 26, wherein the valvemember 26 is configured to abut against this stop member 27 in itsclosed position. The valve member 26 is preferably spring-loaded so asto assume its closed position under the effect of the spring force froma spring member (not shown) acting on the valve member 26.

The invention is of course not in any way restricted to the embodimentsdescribed above. On the contrary, many possibilities to modificationsthereof will be apparent to a person with ordinary skill in the artwithout departing from the basic idea of the invention such as definedin the appended claims.

1. A leak preventing device for preventing liquid from leaking out of adamaged tank (2), wherein the leak preventing device (1) comprises: afloating body (4) with a buoyancy which makes it capable of floating atthe surface (3) of the liquid in the tank (2) with at least an upperpart of the floating body (4) located above the surface (3) of theliquid in the tank (2); and a flexible hose (5) with a first end (6 a)and an opposite second end (6 b), the first end (6 a) of the hose beingfixed to the floating body (4) and the hose (5) being fixed to a wall(7) of the tank (2) at a point of attachment (8) at a distance from saidfirst end (6 a), wherein the hose (5) extends freely inside the tank (2)between the floating body (4) and said point of attachment (8) and thesecond end (6 b) of the hose is connected or connectable to a suctionside of a vacuum pump (9) to allow gas to be drawn off via the hose (5)from a gas-filled space (10) in the tank (2) above the surface (3) ofthe liquid in the tank (2) to produce an underpressure in said space(10).
 2. A leak preventing device according to claim 1, wherein saidfirst end (6 a) of the hose is fixed to the floating body (4) in such amanner that the hose (5) projects from the underside (17 a) of thefloating body at the centre thereof.
 3. A leak preventing deviceaccording to claim 1, wherein a suction channel (18) is arranged in thefloating body (4); the suction channel (18) has an inlet opening (20) atits upper end, this inlet opening (20) is arranged in a part of thefloating body (4) which is configured to be located above the surface(3) of the liquid in the tank (2) when the floating body (4) is floatingat the surface (3) of the liquid in the tank (2); and the first end (6a) of the hose is connected to a lower end (19 a) of the suction channel(18).
 4. A leak preventing device according to claim 3, wherein a checkvalve (25) is arranged at the inlet opening (20) of the suction channel(18) to keep the inlet opening closed when no gas to is drawn off viathe hose (5) from said gas-filled space (10) in the tank (2).
 5. A leakpreventing device according to claim 3, wherein the inlet opening (20)of the suction channel (18) is provided at an upper end of a pipe (21)which projects from the upper side (17 b) of the floating body (4); andthe upper end of said pipe (21) is received in a cover (22), which isconfigured to prevent liquid from splashing into the suction channel(18) through the inlet opening (20).
 6. A leak preventing deviceaccording to claim 3, wherein the suction channel (18) extends acrossthe floating body (4) from the underside (17 a) of the floating body tothe upper side (17 b) thereof.
 7. A leak preventing device according toclaim 1, wherein said second end (6 b) of the hose is connected to ashut-off valve (11), which is fixed to the tank (2) and accessible fromthe outside of the tank (2).
 8. A leak preventing device according toclaim 7, wherein said shut-off valve (11) is connected to a couplingmember (13), which is configured for releasable engagement with acorresponding coupling member (14) arranged at an end of a suction hose(15) from a vacuum pump (9).
 9. A leak preventing device according toclaim 7, wherein the flexible hose (5) is connected to one or morefurther shut-off valves (11), which are fixed to the tank (2) at adistance from each other and accessible from the outside of the tank(2); and each such further shut-off valve (11) is connected to acoupling member (13), which is configured for releasable engagement witha corresponding coupling member (14) arranged at an end of a suctionhose (15) from a vacuum pump (9).
 10. A leak preventing device accordingto claim 9, wherein the shut-off valves (11) are connected to each otherby connecting pipes (16) mounted to the tank (2) on the outside or onthe inside thereof.
 11. A tank for transporting liquid, wherein the tank(2) is provided with a leak preventing device (1) according to claim 1.12. A leak preventing device according to claim 2, wherein a suctionchannel (18) is arranged in the floating body (4); the suction channel(18) has an inlet opening (20) at its upper end; this inlet opening (20)is arranged in a part of the floating body (4) which is configured to belocated above the surface (3) of the liquid in the tank (2) when thefloating body (4) is floating at the surface (3) of the liquid in thetank (2); and the first end (6 a) of the hose is connected to a lowerend (19 a) of the suction channel (18).
 13. A leak preventing deviceaccording to claim 12, wherein a check valve (25) is arranged at theinlet opening (20) of the suction channel (18) to keep the inlet openingclosed when no gas to is drawn off via the hose (5) from said gas-filledspace (10) in the tank (2).
 14. A leak preventing device according toclaim 12, wherein the inlet opening (20) of the suction channel (18) isprovided at an upper end of a pipe (21) which projects from the upperside (17 b) of the floating body (4); and the upper end of said pipe(21) is received in a cover (22), which is configured to prevent liquidfrom splashing into the suction channel (18) through the inlet opening(20).
 15. A leak preventing device according to claim 14, wherein thesuction channel (18) extends across the floating body (4) from theunderside (17 a) of the floating body to the upper side (17 b) thereof.16. A leak preventing device according to claim 13, wherein the suctionchannel (18) extends across the floating body (4) from the underside (17a) of the floating body to the upper side (17 b) thereof.
 17. A leakpreventing device according to claim 12, wherein the suction channel(18) extends across the floating body (4) from the underside (17 a) ofthe floating body to the upper side (17 b) thereof.
 18. A leakpreventing device according to claim 5, wherein the suction channel (18)extends across the floating body (4) from the underside (17 a) of thefloating body to the upper side (17 b) thereof.
 19. A leak preventingdevice according to claim 4, wherein the suction channel (18) extendsacross the floating body (4) from the underside (17 a) of the floatingbody to the upper side (17 b) thereof.
 20. A leak preventing deviceaccording to claim 15, wherein said second end (6 b) of the hose isconnected to a shut-off valve (11), which is fixed to the tank (2) andaccessible from the outside of the tank (2).